1. Technical Field of the Invention
The present invention relates to a process of obtaining dried flower blooms and other dried, natural products such as flower stems, leaves, fruits, vegetables and insects. The invention also relates to the product resulting from the process.
2. Description of the Related Art
Drying flowers is one of man's oldest activities. Archaeologists often find dried flowers among the artifacts of ancient peoples. Modem scientific methods of drying probably started with Ernst Pfitzer, a professor who in Heidelberg, Germany invented the process of solvent dehydrating flowers (1895 U.S. Pat. No. 547,227). At an unknown time prior to Professor Pfitzer, drying flowers with warm forced air (kiln drying) was invented (perhaps at the beginning of the machine age). During World War II a high water absorbent capacity silica gel was first made and immediately became widely used for drying flowers. Silica gel drying produces flowers of higher quality and durability than air, but slow drying times and high labor costs limited it's commercial application. Another important development during WW II was the vacuum freeze drying process which was perfected and used primarily for the production of pharmaceuticals. Only during the last 10 years has vacuum freeze drying been used commercially to dry flowers.
Four drying processes are widely used in commerce today: 1) Traditional air drying achieved by hanging flowers in warm, dry places; 2) Hot air kiln drying is used to produce bunches of low quality dried flowers in a short time; 3) Silica gel drying is used by florists, botanical gardens and hobbyists that are interested in high quality, long lasting dried flowers; and 4) Vacuum freeze dried flowers which are a fast growing market segment because attractive flowers can be produced with little labor. Unfortunately, vacuum freeze dried flowers are filled with voids left by the removed ice and water. ("Freeze dried" flowers is a bit of a misnomer since most of the hydrogen oxide is removed from the melted liquid and not by sublimation). The voids make the dried flowers fragile and cause rapid fading of color. The flower sealer described in my U.S. Pat. No. 4,783,351 is useful in minimizing, but not completely remedying, these shortcomings. Other deficiencies of vacuum freeze drying are the long process times of 7 to 14 days, the high cost of the equipment and reported frequent, costly equipment failures.
My present invention combines the better features of silica gel drying with the better features of vacuum freeze drying in that the dried flowers are produced quickly and with comparatively simple equipment. The dried flowers are compressed by the force of the vacuum on the silica gel and are also free of voids caused by freeze drying. Their colors are brighter and longer lasting than those made by any other known process.
Many attempts have been made in the past to speed-up the silica gel process for drying flowers by heating the covered flowers. All have been relatively unsuccessful because the heat needed to substantially increase drying time at ambient pressure significantly degrades flower colors. Also, the high heat softens the flower to such an extent, before it has lost all it's moisture, that the sharp silica gel becomes imbedded in the flower. When the flower is completely dried the silica gel cannot be removed.